Across
- 3. The layer of rock between the Earth’s crust and core.
- 5. A movement or trembling of the ground that is caused by a sudden release of energy when rocks along a fault move.
- 7. drift, The hypothesis that a single large landmass broke up into smaller land masses to form the continents, which then drifted to their present locations; the movement of continents.
- 10. plate boundary, The edge between two or more plates classified as divergent, convergent, or transform by the movement taking place between the plates.
- 12. The location within Earth along a fault at which the first motion of an earthquake occurs.
- 13. boundary, The boundary between tectonic plates that are colliding.
- 15. The central part of Earth below the mantle.
- 16. plate, A block of lithosphere that consists of of the crust and the rigid, outermost part of the mantle.
- 17. boundary, The boundary between tectonic plates that are sliding past each other horizontally.
- 19. The strong, lower part of the mantle between the asthenosphere and the outer core.
- 21. tectonics, The theory that Earth’s outer layer is made up of large, moving pieces called tectonic plates; the theory explains how plates interact and how those interactions relate to processes such as earthquakes and mountain building.
- 22. spreading, The process by which new oceanic lithosphere (sea floor) forms when magma rises to Earth’s surface at mid-ocean ridges and solidifies, as older, existing seafloor moves away from the ridge.
- 24. The thin and solid outermost layer of Earth above the mantle.
Down
- 1. boundary, The boundary between two tectonic plates that are moving away from each other.
- 2. The soft layer of the mantle on which the tectonic plates move.
- 4. The process by which one lithospheric plate moves beneath another plate as a result of tectonic forces.
- 6. rebound, The sudden return of elastically deformed rock to its undeformed shape.
- 8. The solid, outer layer of Earth that consists of the crust and the rigid upper part of the mantle.
- 9. reversal, The process by which Earth’s magnetic north pole and magnetic south pole switch positions periodically; a change in the direction in which Earth’s magnetic field points.
- 11. current, Any movement of matter that results from differences in density; may be vertical, circular, or cyclical.
- 14. The bending, tilting, and breaking of Earth’s crust; the change in the shape of rock in response to stress.
- 18. A system of ideas that explains many related observations and is supported by a large body of evidence acquired through scientific investigation.
- 20. The point on Earth’s surface directly above an earthquake’s starting point, or focus.
- 23. A break in a body of rock along which one block moves relative to another.